All publications herein are incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Polyvinyl acetal resin has excellent film formation properties and has a unique chemical structure so as to have good adhesion to glasses, metals, ceramic powders, plastics, leathers, and wood. Since polyvinyl acetal resin has various excellent physical properties, it is widely used in the interlayer film for bonding of safety glass used in automobiles and buildings, wash primer, baking varnish, wood lacquer, printing ink, adhesive for electronic ceramic and printed circuit board, metal and metal, metal and plastic, modifiers for hot melt adhesive, and so forth. New uses are also being developed and applied continuously in various industries.
The aforesaid safety glass is usually a laminated glass, also known as a sandwich glass. The laminated glass is held in place by an interlayer film, typically of polyvinyl butyral (PVB) or ethylene-vinyl acetate (EVA), positioned between two or more layers of glass. Laminated glass possesses good safety features because it produces only a small amount of glass fragments when subjected to an external impact. As such, laminated glass is widely utilized in many fields like vehicles, boats, visors, and buildings. On the other hand, laminated glass also possesses good sound-insulating property.